The invention concerns a microscope, especially but not limited to a stereomicroscope, with at least two tubes with an adjustable ocular and an automatic means of adjustment dependent on the other eye to adapt the optical properties of the ray path in the microscope to the optical properties of the user's eyes.
In microscopy, the microscope is a means to enlarge small objects. Those objects must often be transported or moved manually. Frequently it is necessary to manipulate them, as is particularly the case in surgical microscopy. In manipulation of objects, various conditions prevail which often make it difficult or undesirable to operate the adjustments of the microscope. Nevertheless, adjustment of oculars is an important procedure to give the user an optimal and non-fatiguing view of the object. Due to a certain adaptation or fatigue behavior of the eye, it is often necessary to readjust the oculars. With the means available at the state of the technology, that requires interrupting the manipulations under the microscope so that the oculars can be adjusted manually. That is undesirable, though, and that gives rise to the first objective on which the invention is based:
The magnifying system, with its ocular, must be of such a nature that it can be adjusted without using hands. The physiological difference between two eyes of the user should be taken into consideration. The existing standard, by which the difference in visual acuity between two eyes would be compensated for by adapting just one ocular should be replaced so as to compensate for variations in visual acuity of both eyes during a period of observation, thus preventing symptoms of fatigue.
This objective is achieved by use according to the invention of a microscope with the features of claim 1.
Means of remotely controlled adjustment of an ocular are, to be sure, already known in themselves, as, for example, from European Patent Application 2-625332.
There an automatic ocular adaptation according to measured physiological characteristics of the user's eyes is recommended. Although the use of such a system for a microscope is mentioned in this document, it was apparently not recognized at that time that adapting to just one of the user's eyes is inadequate to attain optimum comfort, as that can cause fatigue phenomena, headaches, etc., which can have unpleasant consequences during surgery on humans or animals. Continuous readjustment of the objective focusing, which is done in that patent, as previously, hardly helps, as that, too, must be controlled by the user. That requires that the user concentrate on the adjustment process rather than freeing the user to carry out his real work under the microscope.
Japanese Patent Application 66340 refers to binoculars with magnification compensation in the binocular for both the user's eyes, as well as automatic matching of the two ocular beam paths to the distance between the user's eyes. It is not obvious, though, to apply teachings from another field of optics directly to microscopy. Also, in practice different experts have evolved who have caused the development of the individual specialties to diverge from each other. That also explains why the later European Patent Application makes no reference to the earlier Japanese Patent Application or to its teaching about using magnification compensation in both beam paths.
An adjusting system according to the invention can be achieved with various means. In any case, it requires a motor drive for each ocular and remote control for that drive, which may also be voice-controlled if desired, or which can be triggered or operated by means of a user's extremities; e.g., by his feet. Remote controls operated by other persons at the wish of, and under the instruction of, the user are also conceivable.
This first step of the invention yields enormous advantages for various applications. In the field of surgical microscopy, for instance, it was always extremely difficult to adjust oculars for the operator under the aseptic conditions required. As soon as the operator brings his head near the microscope there is a danger that his breathing, or accidental contact of the oral mask, etc., with the microscope will contaminate the tube part of the microscope. Thus a later manipulation by the operator or an assistant of the usual adjustment mechanisms in the tube part was always linked with a risk of contaminating the outside of the sterile surgical glove. Then the only way to avoid potential subsequent contamination of the patient was to replace the gloves. That was time-consuming and therefore very stressful. Pre-adjustment of the oculars before surgery was not sufficient because, as already noted, the optical properties of an eye are subject to variations which depend on the current state of the user.
This current state of the user can change, though, and generally requires repeated readjustment of the oculars. By means of the invention, though, all human manipulation of the microscope is unnecessary. Refocusing of the main objective to adapt to changed optical properties of the user's eye can be omitted if the object-microscope distance remains the same. That is, of course, also advantageous if the users are changed.
The automatic and continuous adjustment for each eye, according to measured criteria, also eliminates an unpleasant phenomenon that has been unavoidable. That happens when the user, in making an ocular adjustment, accidentally calls on the adaptive ability of the eye, so that the adjustment is not made optimally. That also causes a certain fatigue of the eye which can in some circumstances result in head pain or similar discomfort.